The present invention relates to an ammunition body.
Two stage warheads, also called tandem warheads, are used amongst other things against relatively thin armour plating and cabins having delicate contents, for example helicopters, aeroplanes and ships. The preliminary charge used here belongs to the so-called projectile-fanning charges (self-forging fragments) and has the task of punching or boring as large a hole as possible in the target.
A warhead having a tandem charge is disclosed inter alia in EF-AI-O 583 642 and is integrated in a bazooka to combat an opponent who has taken cover. The protective wall or barricade, for example, is shot through by a hollow charge; a follow-up charge generates splinters behind the cover. In the case of hard targets, ignition at the cover is effected by way of piezo igniters and, in the case of soft targets, by means of proximity igniters. The follow-up charge essentially has to be initiated after a time delay in order not to endanger the gunner, amongst other reasons. These warheads are disadvantageous in that the second charge, or follow-up charge, has to have a relatively small calibre in order to be able to penetrate into the target area. Accordingly, it can only have a limited effect in the actual target. Likewise, owing to the relatively small effective body, a use-dependent time delay is necessary for this latter to be ignited as near as possible to the actual target to be destroyed or affected.
Warheads of this type are therefore unsuitable for targets with redundant devices such as for example helicopters or ships, since their limited effect is either compensated by a back-up system and/or is additionally reduced or even eliminated by an inner bulkhead.
GB-A-I,051,407 discloses an armour piercing shell having two charges. To achieve an overcalibrated hole, a preliminary charge having a projecting rotationally symmetrical lining is proposed. An effective charge arranged downstream should be able to penetrate easily arid deeply into the target through this hole. Practical tests and computer simulations have shown however that this does not work since the resulting ring-shaped and collapsed hollow charge beam widens greatly before the target and loses its cutting effect. By comparison with conventional hollow charges, the arrangement reduces the penetration force rather than increasing it. Moreover, its force is largely angle-dependent, that is to say an oblique-angled strike of the ring-shaped, wide beam leads to its deflection in the target and demonstrates no useful effect.
Similar results can also be observed in the case of a hollow charge according to the exemplary embodiments of FR-E-73 306. Here, the discontinuities and the steep gradients in the lining profile have a particularly negative effect; these linings collapse. The maximum achievable borehole diameter is not larger than that of the notorious conical or bell-shaped linings. Shaped charges are also known (U.S. Pat. No. 2,809,585) in which inert bodies are arranged downstream of the lining of the conical preliminary charge, said inert bodies on the one hand guiding the detonation waves and on the other hand preventing the follow-up charge or the projectile downstream from being adversely influenced by the detonation face of the preliminary charge. [This known charge at the same time displays the features according to the precharacterising clause of the process claim 10.] The subject-matter results in improved system reliability but can only be used for the follow-up charges illustrated which are small with respect to the preliminary charge. Here too, the borehole achieved by the preliminary charge is only approximately the conventional 0.4 times the calibre of the preliminary charge.
A further hollow charge having one or more conically projecting linings is disclosed in U.S. Pat. No. 5,663,475. This hollow charge is principally intended for applications within oil exploration and delivery. Here, the explosive charge and the hollow charge are located in a solid guide anvil which serves to guide the beam. This arrangement produces bores in the target which are smaller than the calibre size and tends to result in extensive power losses as a result of the external beam control, which has a negative effect on the penetration depth of the ring-shaped beam.
A spherical lining characterised by three radii is described in U.S. Pat. No. 5,320,044. This lining is intended to generate two beams, a leading and a lagging beam, in order to achieve deeper penetration in the target. The necessary acceleration of the lining is effected by an overdimensional, large calibre explosive charge, the diameter of which projects by a multiple beyond the lining. The bore which may be achieved in the target is consequently only a fraction of the calibre of the explosive charge.
It is therefore the object of the invention to provide an ammunition body which can create an overcalibrated bore in the target and, where necessary, delivers a large effective charge into the target. It should be possible to use the ammunition body for combating transport or fighter helicopters or in torpedoes against underwater or surface targets. Here, the opening in the target created by the preliminary charge is intended to clear the path for a large effective charge and should not impede this latter.
It should also be possible to use the subject-matter of the invention for civilian purposes, in particular in poorly accessible places where, owing to limited space, the application of conventional drilling methods is either impossible or is very time consuming and expensive in terms of materials.
This object is achieved by an ammunition body and a process for using it, wherein the ammunition body has a shaped preliminary charge with a ductile metal front lining extending across the entire front face of the charge. The lining is rotationally symmetrical about a central axis and is continuous between a periphery of the lining and an axial region, the gradient of the lining not exceeding the absolute value of 0.9.
The inventive construction of the preliminary charge has the surprising effect that the borehole it creates is larger than the calibre of the preliminary charge itself, without the penetration force (bore depth) being significantly smaller than that of conventional cutting charges. As a result, one or more effective charges can be connected in series, these having a high explosive effect or other properties which are effective in combating the specific target.
As a result of its ignited charge, the lining as such becomes a stable projectile in the form of a fragmented, greatly widened ring, which, owing to its size, flies past any components such as sensors and/or electronics which may be arranged upstream, and therefore does not cause them to cease operating prematurely.
The shape of the projecting lining, also called an insert, differs from that known in the specialist literature; the basic literature on hollow charges assumes that a lining has to be of a concave construction, that is to say not conical or bell-shaped, in its axial region.
The lining according to the invention is made of those ductile materials, such as aluminium, iron, electrolytic copper, lead or tantalum, which are known per se for this purpose, and punches out an overcalibrated disc in the target, through which one or more large effective charges can penetrate deeply and without difficulty, that is to say without extensive kinetic losses.
The invention may utilize a distance igniter, which covers any form of proximity igniter, in the simplest case a double cover having an inner contact triggering the igniter on impact against the target. In the case of stationary applications, for example for civilian purposes, this means ignition at a distance (stand-off) of at least one calibre from the target or from the surface in which a bore is to be produced.
Upon striking the target, a lining constructed in accordance with the invention acts as a greatly-accelerated cutting ring whereof large-surface fragments rotate into the ideal orthogonal position with respect to the target during their flight and penetrate said target with great-energy. In practice, in a manner analogous to punching in metal processing, a circular blank having an inner disc which is completely separated from the surrounding area is produced in the target.
The resulting differential acceleration of the cutting ring is only minimally affected by an oblique striking angle and produces a high penetration force even at large distances from the target.
For military purposes, the subject-matter of the invention relates in particular to tandem or multiple warheads.
The ammunition body of the invention with a projecting axial region produces a favourable beam form, so that a widened cutting ring is created.
A lining having an axial region thickness greater than peripheral region thickness, and having a spherical three-dimensional shape, is favourable. The lining may also be constructed with the same or different radii of curvatures for the front and rear surfaces of the lining to define further advantageous embodiments.
The incorporation of linear surfaces of revolution may be likewise advantageous.
As a result of including inert bodies, it is possible to additionally optimise the effect of the detonation wave on the lining.
A maximum effect in the target is produced by connecting in series effective charges having different characteristics, for example charges which first of all have a gas pressure effect and then form splinters.
The process of using the inventive ammunition body comprising the ignition of a preliminary charge at a distance of 2 to 10 times the calibre of the ammunition body, followed by generation of a cutting beam by the line to create a bore in the target of a diameter of 1.0 to 2.2 times the calibre leads to optimum use of the ammunition body [according to the invention] and can be adapted to special targets to be combated; for example in that the follow-up effective charges make full use of the opening created by the preliminary charge, and all the charges are adapted to each another, the armour plating and the actual effective depth required in the target.
The delayed ignition of the effective charge, which is known per se, is particularly effective in increasing the combat force, since said effective charge can penetrate through the large opening created by the preliminary charge and well into the target with a high degree of kinetic energy. Here, it is readily possible to make full use of the total diameter of the calibre of the effective charge.
The ammunition body is preferably utilized for combating relatively lightly armoured targets, such as helicopters. It also can be used in numerous civilian applications in particular in connection with the exploration, delivery and transport of minerals and pumpable media.